252 million years ago the largest extinction event occurred at the end of the Permian age. It wiped out almost 90 percent of all life in water. So far researchers had assumed that the ecosystems gradually recovered from this catastrophe over a long stretch of eight to nine million years and that large predators at the uppermost end of the food chain were the last to reappear.

About 65 million years ago, an asteroid or comet crashed into a shallow sea near what is now the Yucatán Peninsula of Mexico. The resulting firestorm and global dust cloud caused the extinction of many land plants and large animals, including most of the dinosaurs.

Dinosaurs were the largest animals to ever walk Earth, and they ruled the planet for more than 160 million years. The long-necked Argentinosaurus, with back vertebrae almost two metres high, possibly grew to 30 metres long and weighed up to 80 tonnes. So did the earth really shake for them when they mated?